Organic light emitting diodes have advantages such as self-luminescence, wide viewing angle, wide color gamut, fast response, high luminous efficiency, low operating voltage and so on, and are widely used in fields such as display panels. In the organic light emitting diode, microcavity effect means that, where a light emitting region of the organic light emitting diode is located in a resonant cavity composed of a total reflection film and a semi-reflective film and the wavelength of light emitted from the light emitting region is of the same order of magnitude as the cavity length of the resonant cavity, the light of the wavelength is selected and strengthened.